The present disclosure is directed to a method and an apparatus for repairing windshields. While an automobile windshield is a sheet of glass, it is a composite layer for safety. Simple plate glass is not permitted in automobiles because the glass shards scatter badly upon breaking and risk injury. For a number of years, the glass has been formed of a sandwich or composite layer. It is called safety glass for that reason. Safety glass includes an exposed front layer of glass, a similar back layer of glass, and a center layer of adhesive resilient material. The adhesive layer keeps the pieces from scattering. The adhesive layer is incorporated so that the glass of the two exposed layers will not explosively scatter thereby injuring passengers. Moreover, the adhesive layer holds the windshield together in the event of road hazard damage to the glass.
Road hazard damage occurs typically where a leading vehicle either drops a small pebble or the tires of the vehicle sling such a pebble and a trailing vehicle is struck by it. This forms a typical ding in the glass which is a small crater where a dimple is formed. Safety glass normally responds by confining the dimple to one of the two outer layers. Most commonly, the exposed or front outer layer forms a dimple, i.e., a small crater is chipped in it. The damage does not go all the way through the several layers of the safety glass; rather, it is confined to the front layer. Sometimes, the front layer will not be damaged at all but the damage will be confined to the exposed layer on the interior of the vehicle. That layer may form a similar crater or dimple. The difference arises in that the glass layer on the interior of the vehicle forms a reactive dimple at the location where struck. Either type of damage is equally distracting to the driver.
Most vehicle owners take the attitude that a few dings or dimples in the windshield are simply the common and accepted road hazard for driving a vehicle. They will not spend the money to replace the entire windshield. While that can run several hundred dollars, they sometimes merely neglect the dimple, or they seek a repair of the small dimple. When several dimples accumulate on a windshield, perhaps the owner will then replace the entire windshield, but that often is constrained by the rather expensive cost of the wholesale repair, i.e., replacement of the entire windshield. It is possible for the safety glass in the side and back windows to be damaged, but that is relatively rare because the damage primarily arises when the vehicle is traveling at relatively greater speeds on the open highway. The relative motion of the vehicle provides sufficient differences in velocity of the thrown pebble so that dimpling does occur.
Repairs have been attempted in the past. Tacky resin materials have been applied, somewhat in the fashion of putty, which is smeared in the hole or dimple and surplus is then wiped away. As a generalization, the visually distracting dimple is observed by the driver because there is a sharp change in light transmission through the multiple layers of the safety glass. The dimple area is larger than life because of that change in light transmission. Many of these dimples, however, cannot be easily fixed. It is a matter of random breakage. Sometimes, the break or damage is easily accessed to enable use of a spatula to apply a putty-like resin which thereafter cures to fill the dimple. In another aspect, the dimple surface, after weathering, becomes more difficult to work with. The exposure to weathering on the inside of the dimple changes the texture of the surface. In particular, the adhesive layer becomes hardened and less tacky. This changes the ready acceptance of the adhesive layer to a putty of resin to fill the dimple.
The present disclosure sets forth a method and apparatus for such repairs. More specifically, this equipment and procedure cleans up the interior of a dimple. In particular, if the damage is simply a crack, the present disclosure sets forth a procedure by which the crack can also be repaired. As a first step, pressure is applied on the opposite side which tends to open the crack ever so slightly. A portion is drilled away through the outer layer of glass down to the adhesive layer. This provides better exposed surfaces. The exposure, however, is rather short in duration so that the surfaces do not weather and become more difficult to work with. After applying pressure to the back side and drilling away a portion, a resin is then delivered into the crack, now in the form of a drilled hole, and the crack is filled and leveled to the surface. Because it is applied under some pressure, it more uniformly fills the crack and avoid possible bubbles which might otherwise create visual distractions in the repaired windshield. The present apparatus can be used to repair both cracks and dimples. It can also be used to make repairs on the exposed or front face of the windshield. It, likewise, is effective on the inside face where reverse dimpling sometimes occurs. Repairs at all locations can be made. The disclosed invention is useful to assure that repairs carried out in the windshield result in near perfect optical clarity. The clarity is enhanced by resin packing as noted. Moreover, the resin packing is done in such a fashion or in such a way that the finished product is substantially transparent so that the region or area of the repair to a dimple or crack can often be visually equal to the new windshield clarity.
The equipment of this disclosure should be noted. On the side at which the repair is undertaken, that region is contacted by a suction cup which holds a rigid frame member. The suction cup assures connection. The frame member is held in a parallel position with respect to the windshield. It rests on a tripod of three spaced legs. The tripod is constructed so that it supports a projecting tip over the region of the crack or dimple. It supports and thereby aligns a support member so that drilling is at right angles and is accomplished to the desired depth and location. A threaded container for receiving an epoxy resin is also incorporated. The threaded container includes an axially movable plunger so that it functions as a syringe to inject the necessary resin into the damaged glass area where drilled. If drilling turns out to be unneeded, it injects into the dimple or damaged area. That damaged area is forced outwardly so that the glass is bowed slightly by an apparatus placed on the opposite side. Through the use of multiple suction cups, a support member is attached, and a bolt is mounted and located on the opposite side of the dimple or crack. The bolt is extended, contacts against the glass, and bows the glass ever so slightly at that area. This opens up the dimple or crack somewhat for receiving the uncured resin. On curing, the bolt is removed, thereby restoring the windshield to its initial planar condition so that the grip on the repair material is firm and tight. Mention has been made of the apparatus above and that will be detailed substantially in the description of the preferred embodiment which follows.